Vitrifiable coating composition



Patented June 29, 1937 FFEQE VITRIFIABLE COATING COMPOSITION No Drawing.Application April 9, 1935, Serial No. 15,472

12 Claims.

This invention relates to the art of applying fused coatings and moreparticularly to the applying of markings or ornamentation to glass,ceramic or metal surfaces by the application thereto of powdered fusiblematerial that is afterwards fused onto the surface.

In the art of glass making, colors have heretofore been applied to glassby fusing finely ground colored glass onto its surface. Usually thecolored glass is crushed and then finely ground and thereafter suspendedor made into a paste with collodion, a vegetable oil, turpentine orother similar vehicle. The desired design is then formed with theresultant mixture on the surface of the article to be coated and heat isapplied to drive off the vehicle and fuse the finely divided glass ontothe surface.

A major difficulty that has been encountered in the use of this type ofprocess is that the vehicle is either driven off at so early a stage inthe heating that the glass becomes disarranged or entirely falls fromthe surface to which it is to be fused, or that the vehicle carbonizesupon heating or otherwise decomposes or reacts to cause undesirablecoloration or darkening of the finished decoration.

According to the present invention it has been discovered that theaforementioned highly undesirable occurrences may be prevented and fusedcoatings, decorations, or markings may be applied simply andeconomically by using as a vehicle for the finely divided glass certainalkylated aryl compounds and particularly certain alkyl naphthalenes,alone or in a mixture with other materials.

Alkylated aryl compounds are commonly formed either by the reaction ofalkyl chlorides on aryl compounds in the presence of a catalyst such asan aluminum chloride or by the condensation of olefins with arylcompounds, also in the presence of a catalyst. Depending upon theproportions of alkyl and aryl radicals present and upon the extent towhich the reaction is caused or permitted to proceed, mono-alkyl,dialkyl, or higher poly-alkyl derivatives or mixtures containing variousproportions of these derivatives may be formed. In general it has beenfound that for the purpose of this invention it is unnecessary toseparate the various derivatives thatare usually formed but that themixture of monoand poly-alkyl aryl compounds, particularly if itcontains a fairly high proportion of the poly-alkyl compounds, can beused in the form in which it is obtained.

In using such a mixture of alkyl aryl compounds, or using any one alkylaryl compound by itself, the finely ground fusible material which is tobe used in forming the coating or decoration, is ordinarily passedthrough a screen or the like to remove any over-sized particles anddispersed in the vehicle. The resultant mixture, which may vary inconsistency from that of a liquid to that of a rather thick paste, isthen spread upon the surface to be coated in any convenient manner.Commonly, such material is applied with a brush or spray but it can beapplied by dipping the object to be coated. Silk screen stencils havealso been used in applying the coating with excellent results.

After the coating has been applied, the object carrying the coating isheated, as by being placed in an oven, until the vehicle is completelyexpelled and the fusible material welded securely to the surface. Thevehicle used in accordance with the present invention, has been foundparticularly advantageous because it neither releases the fusiblematerial prematurely, nor does it char or otherwise discolor thefinished decoration.

Specifically, it has been found desirable to substitute naphthalene withone or more alkyl groups, such as amyl groups, for the purpose offorming a satisfactory vehicle according to this invention. Thus, as oneexample of the formation of the vehicle, the formation of a mixture ofamyl naphthalenes will be described. It is to be understood, however,that this invention is not limited to the employment of amylnaphthalenes as the vehicle nor to the employment of a mixture ofmonoand poly-substituted amyl compounds. The same general principlesapply to the use of numerous similar alkyl aryl compounds either singlyor in mixtures.

A mixture of amyl naphthalenes well suited for use as a vehicleaccording to this invention and comprising mostly monoand di-amylnaphthalenes has been obtained by reacting 854 parts by Weight ofnaphthalene with 831 parts by Weight of mixed tertiary and secondaryamyl chlorides. A mixture of the two was heated to C. until they formeda homogeneous solution and 10 parts by weight of aluminum chloride werethen added in very small portions. The reaction was substantiallycomplete by the time 8 parts by weight had been added. The mass wasthereafter heated to C. for a few minutes to fully complete the reactionand the resulting products washed with 2% hydrochloric acid, water, 5%sodium hydroxide and then more water.

Upon testing the product by distillation a small amount of amyl chloridewas recovered and 320 parts of naphthalene were found to have been leftunreacted. However, there were 543 parts by weight of mono-amylnaphthalene and 283 parts of di-amyl naphthalene. The mixture of amylnaphthalenes was found to be a satisfactory vehicle for the fusiblematerial just as it was recovered and it was even found possible'to'usethe product of the above reaction, without removing the naphthalene,without serious disadvantage.

In addition to preparing amyl naphthalene by use of the proportionsabove mentioned, other quantities have been used and it has been foundthat if sufiicient amyl chloride is present, for example, 1 to 2molecular weights per molecular weight of naphthalene, a considerableamount of the tri-amyl naphthalene will also be formed. Lowtemperatures, for example, 5-10 C. also favor the formation of thepoly-alkylated derivatives. However, since the boiling points of theamyl naphthalenes are all quite high at ordinary pressures, mono-amylnaphthalene boiling at around 280-3l5 (3., di-amyl naph halene at around325-360 C. and tri-amyl naphthalene at around Mil-390 C. it is ratherdifficult to distill them and hence to determine the exact amounts ofeach formed in any one reaction. For the purpose of this invention itseems sufficient for us to know that these high boiling alkyl arylcompounds, such as the amyl naphthalenes, or mixtures thereof, alloperate satisfactorily according to this invention.

Apparently there is some advantage in having at least a portion of thetri-alkyl derivatives or other poly-alkyl derivatives present because ofthe high temperature at which they boil but it is also desirable to havelower boiling point materials in the mixture. Such lower boiling pointmaterials tend to keep the viscosity down at lower temperatures but boiloff as heat is applied and thus do not unduly lower the viscosity athigher temperatures at which the viscosity of the re.- mainingconstituents is necessarily less because of their increased temperature.Thus not only is it desirable to have mono-alkyl aryl compounds present,but other low boiling point materials, for example, coal tar productssuch as naphthalene or coal tar naptha may be. added for the purpose offurnishing one or more lower boiling point constituents in the vehicleor lowering the viscosity thereof at ordinary temperatures. Likewisealkyl aryl compounds having lower boiling points and possibly lowerviscosities also, may be added. Proportions of these materials cannot beconveniently given here, for they may vary Widely in accordance with thetype of Work to be. done and particularly in accordance with the mannerin which the fusible coating material is to be applied. In spraying ordipping, for example, a

considerable amount of material of low viscosity I may need to beincorporated in the vehicle to provide the necessary fluidity. Instenciling or brushing, however, the coating composition may often berelatively viscous and at times even pasty in nature.

As an example of one type of coating composition that may beadvantageously used in ornamenting glass bottles and the like there maybe used as the vehicle a mixture of isomeric monoand poly-amylnaphthalenes having a boiling range spread between 280-39() C. Thisboiling range may be and preferably is extended downward to around C. bythe addition of naphthalene, coal tar naphtha or other lower boilingpoint constituents of that general nature. The

viscosity at ordinary temperatures is preferably adjusted by selecting alower boiling point constituent that will combine with the amylnaphthalenes to give the desired viscosity. Approximately 0.25 pound ofthis vehicle. is mixed with each pound of the fusible coating materialto be used.

, The coating material ordinarily is comprised of an easily fusiblefinely ground glass but may be comprised of any other type of fusibleceramic material desired. One type of glass which is commonly used as afusible coating material is comprised of 65-75% PbO, around 29% B203 andsmaller'amcunts of silica, alumina, soda, potash,

etc. A pigment of any color may be incorporated in the glass. The glassmay be fused, crushed, ground finely, sieved to remove oversizeparticles, and dispersed in the vehicle.

The mixture of ground glass and vehicle is applied to glass and heatedto fuse the ground glass into position thereon in the usual manner. Theground glass vehicle composition may also-be applied to metal or toceramic material such as pottery or dishes and fused on any one of thesesurfaces in a similar manner. The advantages of a decoration so appliedare rather obvious. The coating is far more. permanent than coatings ofany other type, is highly attractive if properly applied and the objectupon which it is placed can be washed or cleaned without any danger ofinjury to the coating. In fact, when the coating is applied to metal itacts definitely to protect the surface against attack by the weather orby chemical agents.

Amyl naphthalenes have been mentioned specifically as applicableaccording to the principles of this invention and these compounds havebeen found to be especially well suited for the purpose.

It is not the intention, however, to limit the'presa ent invention touse of amyl naphthalenes, but it is intended to include all other alkylaryl compounds of the same general nature and characteristics, for it isquite apparent that they may be used according to this invention with atleast some degree .of satisfaction. 7

As a few examples of other compounds that are usable and as someindication of the types of compounds the use of which is included withinscope of this invention, there may be mentioned in addition to the amylnaphthalenes: amyl benzenes, amyl anthracenes lauryl benzenes,tetradecyl toluenes, amyl diphenyl and the corresponding ethyl, propyl,butyl and hexyl compounds.

Even such compounds as diamyl diphenyl ether, amyl phenyl amyl ether anddiamyl phenol may be used with satisfactory results; These lattercompounds are formed incidentally in the manufacture of alkyl phenols bythe treatment of olefin material with phenol and sulphuric acid. Thustheir use in the above process constitutes an advantageous economicoutlet for products which otherwise have'a limited market.

Any of the compounds mentioned may be mixed in any proportion found tobe desirable with any of the other alkyl aryl compounds or with any ofthe lower boiling point compounds suggested,

to give a mixture that will function satisfactorily,

that is, evaporate at the desired rate and have the desired viscosity.This is a problem of compounding as distinguished from the inventiveconcept that the amyl naphthalenes and similar compounds or mixturesthereof will function as vehicles, evaporating completely within thedesired temperature range and leaving no stains or discolorations in thefused coating.

The composition of the fusible material and of the pigment, and thecompounding and preparation of these ingredients is also variable at thewill of those who practise this invention since the principles thereofapply regardless of the type of fusible material and pigment used.Likewise the invention is not dependent upon whether the coating isapplied to glass, other ceramic material or metal or whether the coatingis applied to the entire object to be coated or merely to a smallportion thereof as a decoration or marking.

I claim:

1. A composition for forming a fused coating comprising a vehicleincluding a compound containing at least one aryl nucleus and at leastone alkyl group directly attached to the aryl nuclcus and boiling ataround 280 to 390 C'., and a finely divided fusible ceramic materialdispersed in said vehicle.

2. A composition for forming a fused coating comprising a vehicleincluding a compound chosen from the class consisting of diaryl ethers,alkyl aryl ethers, and aryl hydroxy compounds, which compounds have beensubstituted in at least one of their aryl nuclei by alkyl radicals, andwhich compounds are capable of being volatilized and driven off from theremainder of the composition at temperatures approximating 280 to 390 0.without imparting any color to the remainder of the composition, and afinely divided fusible ceramic material dispersed in said vehicle.

3. A composition for forming a fused coating comprising a vehicleconsisting of a naphthalene compound having an alkyl radical substitutedfor nuclear hydrogen and being capable of distillation at temperaturesof around 280 to 390 C. without carbonization, and a finely dividedfusible ceramic material dispersed in said vehicle.

4. A composition for forming a fused coating comprising a vehicleincluding an aryl hydrocarbon having alkyl radicals substituted for aplurality of nuclear hydrogen atoms and being capable of beingvolatilized at temperatures of 45 around 280 to 390 C. without leavingan appreciable colored residue, and a finely divided fusible ceramicmaterial dispersed in said vehicle.

5. A composition for forming a fused coating comprising a vehicleincluding a naphthalene hydrocarbon having a plurality of alkyl radicalssubstituted for a plurality of nuclear hydrogen atoms and capable ofbeing distilled from the remainder of the composition at temperatures ofaround 280 to 390 C. without imparting a color to the remainingcomposition, and a finely divided fusible ceramic material dispersed insaid vehicle.

6. A composition for forming a fused coating comprising a vehicleincluding an aryl compound having a plurality of amyl radicalssubstituted for nuclear hydrogen atoms thereof and boiling in thegeneral range of 280 to 390 C., and a finely divided fusible ceramicmaterial dispersed in said vehicle.

7. A composition for forming a fused coating comprising a vehicleincluding an amyl naphthalene, and a finely divided fusible ceramicmaterial dispersed in said vehicle and adapted to form the coating.

8. A composition for forming a fused coating comprising a vehicleincluding a poly-amyl naphthalene, and a finely divided fusible ceramicmaterial dispersed in said vehicle and adapted to form the coating.

9. A composition for forming a fused coating comprising a vehicleincluding a mixture of amyl naphthalenes, and a finely divided fusibleceramic material dispersed in said vehicle and adapted to form thecoating.

10. A composition for forming a fused coating comprising a vehicleincluding a mixture of amyl naphthalenes and an organic compound havinga lower boiling point, and a finely divided fusible ceramic materialdispersed in said vehicle and adapted to form the coating.

11. A composition for forming a fused coating comprising a vehicleincluding a mixture of amyl naphthalenes and naphthalene, and a finelydivided fusible ceramic material dispersed in said vehicle and adaptedto form the coating.

12. A composition for forming a fused coating comprising a vehicleincluding amyl naphthalene and naphthalene, and a finely divided fusibleceramic material dispersed in said vehicle and adapted to form thecoating.

JOSEPH J. SCHAEFER.

